Samsung Galaxy S7 Edge OS installation issue

Hi, As a newbie, I try to install on my phone. Heimdall works well, adb reboot recovery from my Ubuntu 18.4 LTS works well and I arrive to Android recovery modus.
When “Apply update form SD Card”, error 21 occures:
E: failed to verify whole-file signature

E: signature verification failed
E: error : 21

I first wiped out all data/factroy reset and cache partition

Could you help me fix this issue?
thank you!

Regain your privacy! Adopt /e/ the unGoogled mobile OS and online servicesphone

Stockrom Android recovery mode is not meant, but TeamWin - TWRP Recovery > ADB Sideload

Installing a TeamWin - TWRP custom recovery

Steps 1. - 7. as described in the. /e/ documentation

The decisive step starts here:

  • Holding the VOL(-) and HOME and POWER buttons simultaneously until the screen goes dark;

  • as soon as the screen goes dark, immediately release the VOL (-) button and press VOL(+) and HOME and POWER simultaneously until the TWRP Recovery start screen is displayed;

Note: Be sure to reboot into TWRP recovery immediately after having installed the TWRP custom recovery. Otherwise the custom recovery will be overwritten and the device will reboot (appearing as though your custom recovery failed to install) - usually the stockrom Android recovery mode is then displayed again.

The /e/ documentation would be clearer with a few some additional terms (added by me in bold font).

Thank you!
I just arrived to point 7, but my screen turns red and does not moves anymore.
What is turning wrong?

I’ve not seen a red screen at this place yet! Please show a screenshot.

sorry, can not make any photos with the phone anymore…
just managed to turn back to the download mode. Maybe my recovery.img is corrupted.what would you suggest?

Are you in Samsung download mode now?

I am ready! :grinning:

I installed an other version of TWRP and it seems to work.